Jimmy Fallon took over “The Tonight Show” from Jay Leno this evening, but the shift wasn’t what you’d describe as seismic.

The new show has the same familiar format. There’s a monologue, a curtain, a desk, and a band (a great one–the hip-hop group the Roots).

Fallon did bring a new sincerity to the show–he even brought his parents–but time will tell whether he’ll bring the ratings dominance enjoyed by Leno and Johnny Carson.

The 39-year-old Fallon joins a frat-party of late-night hosts on the networks that range from a smart alecky male in his forties (Jimmy Kimmel) to a smart alecky male in his fifties (Craig Ferguson) to a smart alecky male in his sixties (David Letterman).

That’s the networks’ idea of diversity.

The new “Tonight Show” faces two potentially conflicting tasks. Fallon has to bring down the average age of the broadcast, while also maintaining the show’s traditional dominance over the competition. Leno was No. 1 in the ratings for pretty much his entire run, but according to MarketWatch, the median age of his viewers was 58, about a decade older than the demo advertisers crave.

Fallon’s inaugural program tried to strike a balance between entertaining younger audiences and not alienating older ones. The guests included a beloved 45-year-old movie star with a hip-hop background (Will Smith) and a beloved band of fifysomething rockers (U2).

U2′s performance on the roof, with the sun setting on New York City, highlighted one big change for “Tonight”–under Fallon, the show has moved from the West Coast to Manhattan.